It's time to break out the Tassimo brewer and sit back with a novel. This time around I recommend that you use your brewer to brew up a little "Twinnings Chamomile herbal Tea" because you are going to need the relaxation after the stress of dealing with some very complex actions going on in this book.
First of all the master of Science Fiction, Philip K. Dick. returns to Mars for the Setting of "Martian Time-Slip." In this near future version of Mars, Settlements have moved in to tame the wilderness. Society is limited to survival only near the canals of Mars. The rest of the planet is a dry desert. Mars does, however have it's natives, here the Martians are called Bleekmen. The Bleekmen are very human but were settled on Mars at the same time humans began life on Earth. Dick doesn't really go into too much explanation as to where they came from, just that they are. They are not unlike the Aboriginal people of Australia, in that they are dark-skinned and have a rock which holds a religious importance to them.
The settlers on mars have repeated the ideals of the settlers in the new world of North America in the beginnings of the USA, in that they have somewhat enslaved some of the Bleekmen. In the case where a Bleekman is in service of the settlers they are referred to as "tamed Bleekmen." Many of the colonies have a connection to nations on earth, Israel and the United States being the largest and the United Nations is maintaining firm control over the colonies of Mars and due to the constant threat that the Earth could be blown up at any time through nuclear war.
In another aspect of the novel, Dick takes a bit of a jab at the psychiatric community and even claims psychoanalysis as "vainglorious foolishness." Many of the characters of this book could be seen as mentally ill in some form or another, in fact the main character Jack Bohlen is schizophrenic. The schools on Mars are very strict about teaching to those that are in any way mentally ill and it is the Israeli colony that houses a special school / camp for the mentally ill. Here is where the main theme of the book takes off.
One of the mentally ill children is thought to be out of sync with time. One greedy man, Arnie Kott, wants to take advantage of this and use the child, Manfred Steiner, to predict the future. The rumor is that the U.N. will be developing housing for new settlers in the Franklin D. Roosevelt mountains on Mars. The Bleekmen that live there are moving out because this has already started. So Arnie through the help of Jack Bohlen and Manfred Steiner gets sent back 3 weeks in time to prevent this from being a U.N. venture and one of his own ventures so he gets rich from it. But true destiny and fate cannot be changed, at least not in Arnie's sense.
Throughout the book the physics of time travel rise up to make you wonder if it is possible or not. Here's where the chamomile tea comes in to place. You may need to rest your brain after all that trying to figure out time travel. In fact there are sections that are repeated with only little changes that show that you cannot deviate too much from the timestream, so as you are reading the book and you get to a point where you say to yourself, "I have already read this," either you are time-slipping yourself or it's just Philip K. Dick's creative venture of describing time travel. Either way sip the tea and relax.